Field of Invention
Various embodiments of the present invention relate to a network, and more particularly, to a method and apparatus for multi-domain network virtualization.
Description of Related Art
Recent trends of IT (information technology) include server virtualization, VM (virtual machine)-based computing, concentration of IT resources on data center, and network virtualization. Network virtualization is a technology where a plurality of virtual networks may be created on a physical network when necessary and can be deleted. This technology may be utilized to configure a network between virtual machines. A generally used overlay-based virtual network is a L2 network that may be realized on top of a L3 network in an overlay method. In the overlay-based virtual network, tunneling may be performed that is attaching a L3 IP (internet protocol) header to a L2 Ethernet frame being transmitted between virtual machines.
Most representative overlay-based network virtualization includes a VXLAN (virtual extensible local area network) and NVGRE (network virtualization using generic routing encapsulation). In a VXLAN or NVGRE, a virtual L2 network may be created by connecting a tunnel between servers. For this purpose, a full-mesh tunnel must be set between TEPs (Tunnel End Points) being realized in a server or gateway. In order to set a full-mesh tunnel between N number of TEPs, N×(N−1) number of tunnels are needed. This restricts expandability, thereby causing a problem of restricting the size of the network (number of network nodes) where a VXLAN or NVGRE may be applied.
Specifically, the greater the N, the more complex the setting becomes, and due to the restriction on the number of tunnels that may be set in TEPs and the restriction on the number of tunnels that may be managed by one network virtualization manager, a network virtualization domain must be restricted to a certain size. For these reasons, one network virtualization domain may generally be restricted to one IDC (Internet Data Center). There is need for a virtual network existing over a plurality of IDCs located far from one another geographically, but it is not easy to provide these requirements with conventional network virtualization methods since they lack expandability.